MCQ – 74395

The following device shown in the figure used for indirect ophthalmoscopy. What is the power of the lens that should be used with it to visualize the retina?

A.	-58 D
B.	+20 D
C.	+60 D
D.	+90 D

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Correct Answer � B Explanation

Ans: B. +20 D

(Ref Yanoff and Duker 4/e p69; Khurana 6/e p586-587. 5/e p600; Parson’s 22/e p136. 21/e p134).

• With indirect ophthalmoscope, most commonly a lens of +20 D is used.
• Gives a magnification of about 3x (Magnification = power of eye (+60D)/ power of lens).